matrix.js

Array.prototype.clone = function() {
    var arr = this.slice(0);
    for( var i = 0; i < this.length; i++ ) {
        if( this[i].clone ) {
            //recursion
            arr[i] = this[i].clone();
        }
    }
    return arr;
}
var H = {
	DEBUG :true,
	log:function(t){
		if (this.DEBUG)
			console.log(t);
	},
	logMatrix:function(_array){
		var array = _array.clone(); 
		for (var i = 0; i < array.length; i++) {
			array[i] = array[i].join(", ");
		}
		this.log("[\n\t["+array.join("],\n\t[")+"]\n]");
	}
};

function Solver () {
	this.isDoing = false;
}
Solver.prototype.setInput = function(_matrix) {
	this.matrix = _matrix.clone(); 
	this.columnMax = this.matrix[0].length-2;
	this.rowMax = this.matrix.length-1;	
	this.pilot = {
		value : null,
		column : 0,
		row : 0,
		direction : 1
	};
};
Solver.prototype.solv = function() {
	while(this.setNextPilot()){
		H.logMatrix(this.matrix);
		H.log("pilot="+this.pilotToString());

		var i = this.pilot.row + this.pilot.direction;
		while(true){
			H.log("i="+i);
			if ((this.pilot.direction==1 && i >= this.matrix.length) || (this.pilot.direction==-1 && i < 0) )
				break;
			var target = this.matrix[i][this.pilot.column];
			var k = target/this.pilot.value * -1;
			H.log("i="+i+"; "+"target="+target+"; "+"k="+k);
		 	for (var j = this.pilot.column; j < this.matrix[i].length; j++) {
		 		H.log("j="+j);
		 		this.matrix[i][j] += this.matrix[this.pilot.row][j] * k ; 
		 	}
		 	i+= this.pilot.direction;
		}

		if(this.pilot.direction==-1 && (this.pilot.column == 0 || this.pilot.row == 0)) {
			return this.matrix;
		}
	}
	return this.matrix;
};
Solver.prototype.setNextPilot = function() {
	var p = this.pilot;
	var _row = p.row;
	var _column = p.column;
	if (p.value == null) {
		p.value = this.matrix[p.row][p.column];
		while(p.value == 0 && p.column < this.columnMax){
			p.row++;
			if (p.row > this.rowMax){
				p.row = 0;
				p.column++;
			}
			p.value = this.matrix[p.row][p.column];
		}
		if (p.column == this.columnMax && p.value ==0) {
			return false;
		}
		this.matrix.splice(0, 0, this.matrix.splice(p.row, 1)[0]);
		p.row = 0;
		return true;
	};
	p.row += p.direction;
	if (p.row > this.rowMax) {
		p.direction = -1;
		p.row-=2;
	}
	if (p.direction == 1) {
		do{
			p.column++;
		}while(p.column < this.columnMax && this.matrix[p.row][p.column] == 0)

		if (p.column == this.columnMax && this.matrix[p.row][p.column] ==0) {
			if (this.matrix[p.row][p.column+1] != 0) {
				return false;	
			}else if (p.row == this.rowMax) {
				p.direction = -1;
				return this.setNextPilot();
			}else{
				p.column = _column;
				return this.setNextPilot();
			}
		}

		if (this.matrix[p.row][p.column] == 0) {
			p.direction = -1;
			p.row = _row;
			p.column = _column;
			return true;
		}
		if (p.column == this.columnMax) {
			p.direction = -1;
		}
	}else{
		p.column = 0;
		while(p.column < this.columnMax && this.matrix[p.row][p.column] == 0){
			p.column++;
		}
		if (p.column == this.columnMax && this.matrix[p.row][p.column] ==0) {
			return this.setNextPilot();	
		}
	}
	p.value = this.matrix[p.row][p.column];
	return true;
};
Solver.prototype.pilotToString = function() {
	var str = "{";
	for(key in this.pilot){
		str += "\n\t"+key+" : "+this.pilot[key]
	}
	return str+"\n}"
};


// var input =[
// 	[1,-2,1,0],
// 	[0,2,-8,8],
// 	[-4,5,9,-9]
// ];

// var input =[
// 	[1,6,2,-5,-2,-4],
// 	[0,0,2,-8,-1,3],
// 	[0,0,0,0,1,7]
// ];

// var input =[
// 	[2,4,-4],
// 	[5,7,11]
// ];

// var input =[
// 	[1,5,7],
// 	[-2,-7,-5]
// ];

// var input =[
// 	[1,5,7],
// 	[-2,-7,-5]
// ];

// var input =[
// 	[1,-5,1],
// 	[3,-7,5]
// ];

// var input =[
// 	[1,-4,5,0,7],
// 	[0,1,-3,0,6],
// 	[0,0,1,0,2],
// 	[0,0,0,1,-5],
// ];

// var input = [
// 	[1 ,-6,4,0,-1],
// 	[0,2,-7,0,64],
// 	[0,0,1,2,-3],
// 	[0,0,3,1,6]
// ];

// var input = [
// 	[1 ,7,3,0,-4],
// 	[0,1,-1,0,3],
// 	[0,0,0,0,1],
// 	[0,0,1,1,-2]
// ];

//  var input = [
// 	[1,-4,9,0],
// 	[0,1,7,0],
// 	[0,0,2,0]
// ];

// var input = [
// 	[1,-1,0,0,-4],
// 	[0,1,-3,0,-7],
// 	[0,0,1,-3,-2],
// 	[0,0,0,2,4]
// ];


// var input = [
// 	[1,-2,0,3,-2],
// 	[0,1,0,-4,7],
// 	[0,0,1,0,6],
// 	[0,0,0,1,-3]
// ];

// var input = [
// 	[1,3,5,-2],
// 	[0,1,4,-5],
// 	[3,7,7,6]
// ];

// var input = [
// 	[1,-3,4,-4],
// 	[3,-7,7,-8],
// 	[-4,6,-1,7],
// ];

// var input = [
// 	[1,0,-3,8],
// 	[2,2,9,7],
// 	[0,1,5,-2]
// ];

// var input = [
// 	[1,-3,0,5],
// 	[-1,1,5,2],
// 	[0,1,1,0]
// ];

// var input = [
// 	[1,0,3,0,2],
// 	[0,1,0,-1,3],
// 	[3,-2,3,2,1],
// 	[1,0,0,7,-5]
// ];

var input = [
	[1,0,0,-2,-2],
	[0,2,2,0,0],
	[0,0,0,0,0],
	[0,0,1,3,1],
	[-2,3,3,1,5],
];

// var input = [
// 	[0],
// 	[0],
// ];

// var input = [
// 	[0],
// 	[0],
// ];

// var input = [
// 	[0],
// 	[0],
// ];

var s = new Solver();
s.setInput(input);
H.logMatrix(s.solv());
H.logMatrix(input);